JP2802427B2 - Sealed alkaline storage battery and method of manufacturing the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement in a sealed alkaline storage battery.

(Prior Art) Generally, a sealed alkaline storage battery includes a positive electrode mainly composed of nickel hydroxide, a negative electrode mainly composed of cadmium hydroxide, a separator for separating positive and negative plates, potassium hydroxide as an electrolyte, It is composed of an aqueous alkali solution such as sodium hydroxide.

In a normal sealed alkaline storage battery, the capacity of the negative electrode is larger than the capacity of the positive electrode, and the amount of the electrolyte is reduced so that the electrode surface is not sufficiently wet with the electrolyte. The oxygen gas generated is sufficiently consumed by the negative electrode. If the absorption of oxygen gas is poor, the internal pressure of the battery increases at the time of overcharging, so that a large current cannot be charged.

However, in recent years, shortening of charging time has been demanded,
It has been proposed to increase the reaction efficiency between the above oxygen gas and the metal cadmium of the negative electrode in order to improve the rapid charging capability of the storage battery itself.

Since the reaction between the oxygen gas and the metal cadmium of the negative electrode is performed on the surface of the negative electrode, how the three-phase interface between the metal cadmium, which is a solid phase on the surface of the negative electrode plate, the oxygen gas in the gas phase, and the liquid electrolyte is changed Is a very important factor.

That is, if an excessive amount of electrolyte is present on the surface of the electrode plate, the reaction between the metal cadmium and oxygen on the negative electrode plate is hindered due to precipitating, which cannot be carried out efficiently. However, there is a problem that the rapid discharge property tends to be deteriorated and the rapid discharge property tends to decrease.

In order to improve this, Japanese Utility Model Laid-Open Publication No. Sho 59-168959 discloses an "isolator for a sealed lead-acid battery". According to the publication, a hydrophilic separator having excellent adhesion to the anode plate is provided on the anode plate side, and a water-repellent separator having excellent gas holding power is provided on the cathode plate side.

However, in the above prior art, since the boundary between the hydrophilic separator and the water-repellent separator is clearly formed, the amount of the electrolytic solution on the negative electrode plate surface can be adjusted. On the other hand, there is a boundary between the hydrophilic separator and the water-repellent separator, and oxygen gas generated from the positive electrode is blocked by the electrolyte film formed at the interface between the water-repellent separator and the hydrophilic separator. Thus, there is a problem in that this does not easily reach the surface of the negative electrode plate and cannot smoothly proceed. Therefore, the reaction between the oxygen gas and the metal cadmium cannot be sufficiently performed on the negative electrode plate surface.

(Problems to be Solved by the Invention) The present invention has been made intense research in view of the present situation,
Closed type that eliminates the clear boundary between the water-repellent separator and the hydrophilic separator, prevents the formation of an electrolyte film, and efficiently absorbs oxygen gas for cadmium on the negative electrode, enabling rapid charging An alkaline storage battery and a method for manufacturing the same are provided.

(Means for Solving the Problems) In the present invention, a water-repellent layer of a woven or nonwoven fabric made of water-repellent synthetic resin fiber is placed on one surface of a substrate made of a woven or nonwoven fabric made of synthetic resin fiber, and this is placed on a calender roll. The separator is an integral unit, and the electrode plate group wound around the positive electrode plate and the negative electrode plate so that the water-repellent layer is in contact with the negative electrode plate surface is sealed in a housing. -Type alkaline storage battery (Claim 1), and between the positive electrode plate and the negative electrode plate, on one side of a substrate made of a woven or non-woven fabric made of synthetic resin fibers, water-repellency of a woven or non-woven fabric made of water-repellent synthetic resin fibers After placing the layer on a calender roll and integrating it into a separator, the water-repellent layer was sandwiched by abutting the negative electrode surface, and this was formed into a spiral shape to form an electrode plate group. Alkali characterized by being sealed in a housing This is a method for manufacturing a storage battery (Claim 2).

Since the separator in the present invention has a water-repellent layer made of a fluorine resin or the like integrally formed on one side thereof by calendering, the boundary surface between the woven or nonwoven fabric and the water-repellent layer has a rugged shape, and the separator has an electrolytic shape. When impregnated with a liquid, it is not possible to form a continuous film with the electrolytic solution on this boundary surface. That is, portions of the film made of the electrolytic solution and portions to which no film of the electrolytic solution is attached are alternately provided. This makes it possible to easily pass oxygen gas.

Note that the water-repellent layer in contact with the negative electrode is not entirely formed of a water-repellent substance, but is formed of a woven or nonwoven fabric in the water-repellent layer.

The material of the woven or non-woven fabric forming the separator is not particularly limited, and for example, fibers such as nylon, polyvinyl chloride, and polyethylene are used.

(Example) Example (1) A separator having a water-repellent layer integrally provided on one surface as described below is provided between a positive electrode plate mainly composed of nickel hydroxide and a negative electrode mainly composed of cadmium hydroxide as follows. After the layer was brought into contact with the negative electrode surface and sandwiched, it was wound in a group and sealed in a housing to obtain the alkaline storage battery of the present invention.

Thus, the separator is formed by entanglement of 3 denier, 50 mm long nylon fibers with each other to form a layer having a predetermined thickness, and then, the same nylon fibers as above are placed in a 5% PTFE (polytetrafluoroethylene) disk version. The immersed and dried product was rolled on a calender roll, and a nylon nonwoven fabric having a thickness of 0.2 mm, in which a nylon fiber layer and a PTFE-treated nylon fiber layer were integrally formed, was used.

The thickness of the PTFE-treated nylon fiber is about 0.02 mm.

Comparative Example (1) Same as Example (1) except that the separator in Example (1) was replaced with a non-woven fabric separator having a thickness of 0.2 mm in which 3-denier, 50 mm long nylon fibers were entangled with each other. Thus, a comparative alkaline storage battery was obtained.

Comparative Example (2) Instead of the separator in Example (1), a 3-denier, 50-mm long nylon fiber was entangled with each other, and a 0.1-mm-thick nonwoven fabric and the same nylon fiber as above were placed in a 5% PTFE dispersion. A comparative example alkaline storage battery was obtained in the same manner as in Example (1) except that a separator was used in which a water-repellent nonwoven fabric having a thickness of 0.1 mm dried and immersed and dried was used.

In order to test the performance of the thus obtained alkaline storage battery of the present invention and the comparative alkaline storage battery, the charging rate and the peak internal pressure in the battery at the time of overcharging were measured. The result is as shown in FIG.

As is apparent from FIG. 1, the alkaline storage battery of the present invention has a high oxygen gas absorption capacity, so that the internal pressure in the battery shows a lower value than that of the alkaline storage battery of the comparative example. Was confirmed.

(Effects of the Invention) According to the present invention, the three phases of the negative electrode, the electrolytic solution and the oxygen gas can come into contact with each other under optimal conditions. It is very useful industrially.

[Brief description of the drawings]

FIG. 1 is a diagram showing a relationship between a charging rate and a peak internal pressure in a battery at the time of overcharging in a sealed alkaline storage battery of the present invention and a method of manufacturing the same.

Claims (2)

(57) [Claims] 1. A separator formed by placing a water-repellent layer of a woven or non-woven fabric made of water-repellent synthetic resin fiber on one surface of a substrate made of a woven or non-woven fabric made of synthetic resin fiber and hanging it on a calender roll. A sealed alkaline storage battery characterized in that a group of electrode plates wound around the positive electrode plate and the negative electrode plate such that the water-repellent layer is in contact with the surface of the negative electrode plate is sealed in a housing. 2. A woven or nonwoven conical layer made of a water-repellent synthetic resin fiber is placed on one side of a substrate made of a woven or nonwoven fabric made of synthetic resin fibers between a positive electrode plate and a negative electrode plate. A water-repellent layer is held in contact with the negative electrode surface and sandwiched by a separator rolled on a calendar roll to form an integral separator, which is then formed into an electrode group, which is then sealed in a housing. A method for producing an alkaline storage battery, comprising: